Fluid cooling arrangement for electric discharge devices



R. E. MANFREDI FLUID COOLING ARRANGEMENT FOR ELECTRIC DISCHARGE DEVICES Filed July 19, 1952 Fig.1.

Inventor: 1 Robert E,Man1-r-ecli,

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United rates Patent FLUID COOLING ARRANGEMENT FOR ELECTRIC DISCHARGE DEVICES Robert E. Manfredi, Schenectady, N. Y., assignor to General Electric Company, a corporation of New York Application July 19, 1952, Serial No. 299,820

6 Claims. (Cl. 313-44) The present invention relates to the improved cooling of electric discharge devices and particularly to an improved construction for effecting the cooling of the anode and anode seal by forced air or other cooling fluid.

From the standpoint of operation and maintenance of electronic equipment such as broadcast transmitters, for example, it is considered very desirable to employ electric discharge devices utilizing air or other gas cooling in contrast to water or other liquid cooling, because of the simplicity of the structures involved and the lack of maintenance problems. it has been increasingly difiicult to provide satisfactory air cooling in high power equipment particularly at the high operating frequencies now used in much equipment of this type. At higher operating frequencies, it is necessary in order to control the electrical characteristics of the discharge devices to make them of relatively small dimensions. This makes it difficult to provide adequate cooling with forced air, for example. The present invention provides for improved cooling of an electrode forming a part of the envelope of a discharge device, such as the anode, and the associated seal between the electrode and the tube envelope. The construction is also well suited to an air cooled tube which plugs in not only to the electrical connections for the various electrodes but also into the air duct.

The objects and advantages which characterize my invention will become more apparent as the following description proceeds, reference being had to the accompanying drawing and its scope will be pointed out in the appended claims. In the drawing, Fig. 1 is an elevational view partially in section of an electric discharge device and cooling system therefor embodying my invention and Fig. 2 is a sectional view taken along the line 2-2 of Fig. 1.

Referring now to the drawing 1 show my invention applied to a high frequency transmitting tube in which the envelope is made up of alternate conducting and insulating sections, the conducting sections being in the form of annular rings forming the terminals of the various electrodes and the insulating sections being in the form of ceramic cylinders to which the conducting sections are bonded. The tube may be considered an air cooled version of the transmitting tube described and claimed in my co-pending application, Serial No. 275,522, filed March 8, 1952, and assigned to the assignee of this application.

Referring now to the drawing, the discharge device includes a cylindrical anode 1 forming a part of the envelope of the device and joined to the upper end of an anode to screen grid insulator 2 by means of a sealing ring and terminal member 3 which is bonded atone edge to the outer surface of the anode at a region intermediate to the ends thereof and at an intermediate region to the upper end of the insulator 2. The sealing ring is bent back upon itself to provide a cylindrical contact surface 5 at the outer edge thereof and also to provide ice an annular trough designated at 6 which receives cooling fluid directed into the trough by the cooling structure associated with the anode in accordance with the present inventiont As illustrated in the drawing, the anode 1 is an elongated cylinder having a smaller exterior diameter than the interior diameter of the anode-screen grid insulator 2 and the inner end of the anode extends within this insulator. The anode is bored out to provide an active anode surface 7 which cooperates with the remaining electrodes of the device, the screen grid 8 of which is the only one visible in the drawing. The anode extends a substantial distance to the exterior of the envelope from the point of junction with the anode sealing ring 3 and is closed at its outer end by an annular plate 9 and exhaust tubulation 10 which may be protected by a suitable cap 11.

The cooling structure for the anode and the anode seal includes a radiator made up of a number of annular fin members 12 adapted for having a cooling fluid directed thereagainst. The fin members 12 extend in planes transverse to the anode and are flanged at their inner ends as illustrated at 13 to provide for the automatic spacing of the members in the stack and also to provide improved and extended area contact with the anode surface to facilitate brazing thereto. The extended area provides improved heat transfer between the anode and the cooling members. In accordance with the invention, the lowermost member of the stack 14 is made of heavier stock to protect the radiator'and is provided with a plurality of circumferentially spaced apertures 15 facing the anode sealing ring 3 to direct some of the air or other cooling fluid directed against the radiator from the radiator On to the surface of the anode seal and in the specific embodiment illustrated into the annular passage or trough 6 of the terminal member 3.

In a similar manner, the upper member 16 of the radiator assembly is made of heavier stock and as illustrated is also of larger diameter than the remainder of the radiator assembly. Thismember cooperates with the upper wall of an air supply duct 17 to provide a stop member when the discharge device is plugged into a circuit through the air supply duct. As is apparent from an inspection of Fig. 2, the air supply duct 17 is' provided with. side wall extensions 18 and 18a which conform in shape with the outer. surface of the radiator to define aligned spaced upper and lower openings or apertures and terminate short of. one another to provide an exhaust passage on the side of the radiator opposite the p inlet. The stop member 16 restson these members 18 and 13a and also theupper wall of the duct 17. Thus,

the stop member 16 closes the upper opening or aperture when the device is plugged in the duct, and the space between the stop member 16 and the lowermost member 14 is such that the lowermost member 14 is disposed in and closes the lower opening or aperture in the duct.

While the particular construction of the remainder discharge device is not particularly important with respect to the present invention, the illustrated embodiment includes a screen grid terminal ring 19, a screen gridcontrol grid insulator 20, a control grid terminal ring 21 (separated by an insulator not visible in the drawing), a cathode terminal ring 22, a cathode-heater insulator 23 and a heater terminal assembly 24. It will be noted that the terminal rings are of progressively decreasing diameters starting from the anode end of the tube and that the radiator is larger than the anode terminal. With this arrangement, it is apparent that the entire tube may be plugged through the cooling duct into the stationary contacts provided in the circuit apparatus for cooperation with the terminal rings of the various electrodes. In order to facilitate the handling of the tube, a suitable handle 25 is secured to the upper end of the anode cylinder.

It will'be apparent from the foregoing detailed description that the present invention provides a very simple radiator and cooling assembly which permits the easy insertion of the tube into the cooling duct and the circuit connections of the stationary part of the equipment and at the same time provides very simple means for directing a portion of the cooling fluid from the radiator onto the anode seal.

While I have described in detail a particular embodiment of my invention, it will be apparent to those skilled in the art that changes and modifications may be made without departing from my invention in its broader aspects and I aim therefore in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent in the United States is:

1. An electric discharge device comprising a cylindrical anode, a cylindrical insulator having a larger inner diameter than an outer diameter of said anode, a metal sealing ring bonded to said anode intermediate the ends thereof and to said insulator and having a heat radiating portion, and a radiator surrounding said anode and including a plurality of annular metal members mounted in a stack between said sealing ring and the outer end of said anode, the lower one of said annular members being adjacent said sealing ring and having apertures facing said portion to deflect cooling fluid toward said portion.

2. An electric discharge device comprising a cylindrical anode, a cylindrical insulator having a larger inner diameter than an outer diameter of said anode, a metal sealing ring bonded to said anode intermediate the ends thereof and to said insulator, said ring including a flange at the outer edge thereof defining a groove opening toward the outer end of said anode, and a radiator surrounding said anode and including a plurality of annular finmembers mounted in a stack between said sealing ring and said outer end of said anode, the lower one of said fin membcrs' being adjacent said sealing ring and having apertures facing said groove to deflect cooling fluid thereinto.

3.. A cooling duct having an opening therein, an electric discharge device including an envelope and comprising a generally cylindrical anode extending exteriorly of said envelope, and a radiator joined to said anode and including a stack of annular cooling members extending in planes perpendicular to the axis of said anode and disposed in said opening, one of said members being of larger diameter than the remaining members and closing said opening Whensaid envelope is plugged therein,

4. An electric discharge device including an envelope and comprising a generally cylindrical anode extending exteriorly of the envelope of said device, a radiator joined to said electrode including a stack of annular cooling members extending in planes perpendicular to the axis of said anode, duct for supplying cooling fluid to said radiator including spaced walls having aligned apertures receiving said envelope, said duct containing only said radiator when said envelope is plugged therein, and a spaced pair of said members closing said apertures when said envelope is plugged in said duct.

5. An electric discharge device comprising a cylindrical anode, a cylindrical insulator having a larger inner diameter than an outer diameter of said anode, a metal sealing ring bonded to said anode intermediate the ends thereof and to said insulator and having a heat radiating portion, and a radiator surrounding said anode and including a stack of annular cooling members extending in planes perpendicular to the axis of said anode between said sealing ring and the outer end of said anode, the outermost one of said members being of larger diameter than the remaining members to provide a stop member When said envelope is plugged into a cooling duct and the innermost one of said members being adjacent said sealing ring and having apertures facing said portion to deflect cooling fluid toward said portion.

6. An electric discharge device including an envelope and comprising a generally cylindrical anode extending exteriorly of said envelope, a seal between said anode and said envelope, a radiator joined to said anode including a stack of annular cooling members extending in planes perpendicular to the axis of said anode, a duct connected to said device and including spaced walls with aligned apertures, the outermost one of said members being of a larger diameter than the remaining members and engaging one of said walls for closing the aperture therein and positioning said remaining members of said radiator in said duct, the innermost one of said members being disposed adjacent said seal between said anode and envelope, said innermost one of said members closing the aperture in the other of said spaced walls of said duct when said device is plugged in said duct, said innermost one of said members having apertures to deflect a portion of the cooling fluid passing through said duct toward said seal.

References Cited in the file of this patent UNITED STATES PATENTS Haller Sept. 5, 1950 l i i 

